Swing arm assembly with lift assembly

ABSTRACT

A swing arm assembly includes a tip dresser, a flange, and a swing arm. The flange is coupled with the tip dresser. The swing arm includes a mounting base and an arm assembly. The arm assembly includes an arm, an extendible arm mount, and a head. The arm is coupled with the mounting base. The extendible arm mount is disposed within the arm and is slidable with respect to the arm along a first axis between a retracted position and an extended position. The head is mounted to the extendible arm mount and includes a support plate and an actuator. The actuator is coupled with the support plate. The tip dresser is coupled with the support plate. The actuator is operably coupled with the flange to facilitate selective sliding of the tip dresser with respect to the support plate.

REFERENCE TO RELATED APPLICATIONS

The present application claims priority of U.S. provisional applicationSer. No. 62/457,017, filed Feb. 9, 2017, entitled Swing Arm Assemblywith Lift Kit and hereby incorporates the same application herein byreference in its entirety.

BACKGROUND

In spot welding, the electrode tips (weld tips) can get worn and dirtyand are thus cleaned periodically to maintain good quality welds. Whenthe weld gun is carried by a robot, the robot can bring the gun to thetip dresser for cleaning. However, some weld guns are fix mounted andthus utilize a swing arm that brings the tip dresser to the electrodetips for cleaning.

SUMMARY

In accordance with one embodiment, a swing arm for one or more of a tipdresser and a tip exchanger for a spot welding machine is provided. Theswing arm comprises a base, an arm, and a head. The arm is pivotallycoupled with the base. The head is coupled with the arm and comprises asupport plate and a lift assembly. The lift assembly comprises amounting plate and a slidable plate. The mounting plate is coupled withthe support plate. The slidable plate is slidably coupled with themounting plate and is configured to accommodate one or more of a tipdresser and a tip exchanger. The slidable plate is slidable with respectto the mounting plate along an axis.

In accordance with another embodiment, a lift assembly for a swing armfor one or more of a tip dresser and a tip exchanger for a spot weldingmachine is provided. The lift assembly comprises a mounting plate and aslidable plate. The mounting plate is coupled with the support plate.The slidable plate is slidably coupled with the mounting plate and isconfigured to accommodate one or more of a tip dresser and a tipexchanger. The slidable plate is slidable with respect to the mountingplate along an axis.

In accordance with another embodiment, a swing arm for one or more of atip dresser and a tip exchanger for a spot welding machine is provided.The swing arm comprises a base, an arm, and a head. The arm is pivotallycoupled with the base. The head is coupled with the arm and comprises asupport plate and a lift assembly. The lift assembly comprises amounting plate, a slidable plate, an actuator, and a rail and a track.The mounting plate is coupled with the support plate. The slidable plateis slidably coupled with the mounting plate and is configured toaccommodate one or more of a tip dresser and a tip exchanger. Theslidable plate is slidable with respect to the mounting plate along anaxis. The actuator is coupled with the mounting plate and is configuredto facilitate selective sliding of the slidable plate with respect tothe mounting plate. The actuator comprises a piston that is engaged withthe mounting plate. The rail and the track cooperate with each other tofacilitate sliding of the slidable plate with respect to the mountingplate. The mounting plate comprises a flange that is engaged with thepiston. the mounting plate defines a slot and the flange extends throughthe slot.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments will become better understood with regard to thefollowing description, appended claims and accompanying drawingswherein:

FIG. 1 is a perspective view of a swing arm assembly according to oneembodiment, having a tip dresser coupled to the swing arm assembly;

FIGS. 2-5 are various views depicting a head of the swing arm assembly;

FIG. 6 is a perspective view depicting a swing arm assembly according toanother embodiment;

FIG. 7 is a perspective view depicting a swing arm assembly according toyet another embodiment;

FIG. 8 is a perspective view depicting a swing arm assembly according toyet another embodiment;

FIG. 9 is a perspective view depicting a swing arm assembly according toyet another embodiment;

FIG. 10 is a perspective view depicting an alternative embodiment of ahead of a swing arm;

FIG. 11 is a perspective view depicting another alternative embodimentof a head of a swing arm;

FIG. 12 is a perspective view depicting yet another alternativeembodiment of a head of a swing arm;

FIGS. 13-15 are various views depicting yet another alternativeembodiment of a swing arm assembly;

FIGS. 16-19 are various views depicting yet another alternativeembodiment of a swing arm assembly;

FIGS. 20-25 are various views depicting a swing arm assembly having ashifter according to one embodiment;

FIG. 26 is a front perspective view depicting an alternate embodiment ofa lift assembly associated with the head of a swing arm;

FIG. 27 is a rear perspective view depicting the head of the swing armand lift assembly shown in FIG. 26;

FIG. 28 is a front perspective view depicting the lift assembly shown inFIG. 26;

FIG. 29 is a rear perspective view depicting the lift assembly shown inFIG. 26;

FIG. 30 is a side view depicting the lift assembly of FIG. 26 shownattached to a tip dresser;

FIG. 31 is a front perspective view depicting a slidable plateassociated with the lift assembly shown in FIG. 26, where a mountingplate associated with the lift assembly is shown removed to display apair of rails slidably engaged with a pair of tracks;

FIG. 32 is a front view depicting the lift assembly shown in FIG. 26;and

FIG. 33 is a cross-sectional view taken along the line 33-33 in FIG. 32.

DETAILED DESCRIPTION

Embodiments are hereinafter described in detail in connection with theviews and examples of FIGS. 1-33, wherein like numbers indicate the sameor corresponding elements throughout the views. As illustrated in FIG.1, a swing arm assembly 20 is provided that can include a swing arm 22and a tip dresser 24. The swing arm 22 can selectively position the tipdresser 24 with respect to welding tips of a spot welder (not shown) tofacilitate cleaning/dressing of the welding tips. The swing arm 22 caninclude a mounting base 26, an arm assembly 28 pivotally coupled to themounting base 26, and a driver cylinder 29 pivotally coupled to themounting base 26. The driver cylinder 29 can operably mounted to the armassembly 28 to facilitate in pivoting of the arm assembly 28 withrespect to the mounting base 26. In one embodiment, the driver cylinder29 can be a pneumatic drive. In other embodiments, any of a variety ofdrives can be used to facilitate powered pivoting of the arm assembly28, such as, for example, a servo, a rotary servo drive, a gear boxdrive, a linear electric drive, and a hydraulic drive. The arm assembly28 can include an arm 30, an extendible arm mount 32, and a head 34. Theextendible arm mount 32 can be slidably coupled with the arm 30 andslidable between a retracted position and an extended position. The head34 can be mounted to the extendable arm mount 32 and can be configuredto accommodate the tip dresser 24.

The mounting base 26 can facilitate mounting of the swing arm assembly20 to with fasteners (e.g., with bolts), to a floor, or at any of avariety of other suitable locations that allow the tip dresser 24 tointeract properly with the spot welding machine (not shown). Forexample, when the spot welding machine is operating, the swing arm 22can be in a stand-by position, such that the tip dresser 24 remains outof the operational zone of the spot welding machine. Once the weldingtips are ready for dressing, the spot welding machine can cease spotwelding, and the swing arm 22 can pivot the tip dresser 24 into position(via operation of the driver cylinder 29 and/or sliding of theextendible arm mount 32). The spot welding machine can then bring thewelding tips into contact with a cleaning mechanism 36 on the tipdresser 24 to facilitate dressing of the welding tips. In oneembodiment, the swing arm 22 can move the tip dresser 24 into placewithout requiring substantial movement of the spot welder. In anotherembodiment, the swing arm 22 and the spot welding machine can movetogether such that they meet at a predetermined location.

Referring now to FIGS. 2-5, the head 34 can include a support plate 38that is rotatably coupled with a support 40 by a rotational adjustmenttube 42. The rotational adjustment tube 42 can include a plurality offasteners 44 that allow for selective positioning of the support plate38 with respect to the support 40. A pair of vertical adjustment bolts45 can be associated with the support 40 and can facilitate verticalpositioning of the support plate 38 with respect to the support 40. Thesupport plate 38 can include a plurality of adjustment screws (e.g., 46)and adjustment jacking bolts (e.g., 48). As illustrated in FIGS. 3 and4, the tip dresser 24 can be releasably attached to the support plate 38by the adjustment screws (e.g., 46). The adjustment screws (e.g., 46)and adjustment jacking bolts (e.g., 48) can cooperate to permit finetuning of the positioning of the tip dresser 24 upon the support plate38. For example, as illustrated in FIGS. 3 and 4, the spacing of eachside of the tip dresser 24 can be adjusted with the adjustment screws(e.g., 46). Referring again to FIG. 2, the adjustment screws (e.g., 46)can be provided through slotted holes 50 in the support plate 38 thatallow for fine tuning of the rotational position of the tip dresser 24during installation. It is to be appreciated that when the tip dresser24 is attached to the head 34, the positioning of the tip dresser 24 canbe adjusted to ensure proper interaction with the welding tips of thespot welder (e.g., by adjusting any of the plurality of fasteners 44,the pair of vertical adjustment bolts 45, the adjustment screws (e.g.,46) and the adjustment jacking bolts (e.g., 48)).

FIGS. 6-9 illustrate various alternative embodiments of swing armassemblies (20 a, 20 b, 20 c, and 20 d, respectively) that are similarto the swing arm assembly 20 illustrated in FIGS. 1-5 except that theswing arm assemblies (20 a, 20 b, 20 c, and 20 d, respectively) havedifferent arm lengths and the tip dressers (24 a, 24 b, 24 c, and 24 d,respectively) are provided in different orientations.

FIG. 10 illustrates an alternative embodiment of a head 134 for a swingarm assembly, the head 134 being similar to, or the same as in manyrespects as, the head 34 illustrated in FIGS. 1-5. However, the head 134can include an adapter plate 152 releasably secured to a support plate138. The adapter plate 152 can include a plurality of holes 154 that canaccommodate a variety of different tip dressers (not shown).

FIG. 11 illustrates another alternative embodiment of a head 234 for aswing arm assembly, the head 234 being similar to, or the same as inmany respects as, the head 34 illustrated in FIGS. 1-5. However, asupport plate 238 of the head 234 can include a plurality of differentholes 256 that are distributed along the support plate to accommodate avariety of different tip dressers (not shown).

FIG. 12 illustrates another alternative embodiment of a head 334 for aswing arm assembly, the head 334 being similar to, or the same as inmany respects as, the head 34 illustrated in FIGS. 1-5. For example, atip dresser 324 can be mounted to a support plate 338 of the head 334.However, a lift assembly 358 can be releasably secured to the supportplate 338 and can be operably coupled with the tip dresser 324. The liftassembly 358 can be configured to facilitate powered vertical movementof the tip dresser 324 for effective positioning of the tip dresser 324with respect to welding tips.

FIGS. 13-15 illustrate yet another alternative embodiment of a swing armassembly 420 that is similar to, or the same as in many respects as, theswing arm assembly 20 illustrated in FIGS. 1-5. For example, the swingarm assembly 420 can include a swing arm 422. However, the swing armassembly 420 can include a tip exchanger 460 that is configured tofacilitate replacement of tips of a spot welding machine.

FIGS. 16-19 illustrate yet another alternative embodiment of a swing armassembly 520 that is similar to, or the same as in many respects as, theswing arm assembly 20 illustrated in FIGS. 1-5. For example, asillustrated in FIGS. 16 and 17, the swing arm assembly 520 can include aswing arm 522. However, the swing arm assembly 520 can include a tipexchanger 560 that is configured to facilitate replacement of tips of aspot welding machine. The swing arm assembly 520 can also include an XYZservo positioning system 562 (FIG. 18) that includes an X-axis servoslide 564, a Y-axis servo slide 566, and a Z-axis servo slide 568 thatcooperate to facilitate three-dimensional positioning of the tipexchanger 560 with respect to a spot welding machine (not shown). It isto be appreciated that the XYZ servo positioning system 562 can bepowered pneumatically, hydraulically, electrically, or with any of avariety of suitable additional or alternative motive sources.

Embodiments of a swing arm system having a slider or shifter arehereinafter described in detail in connection with the views andexamples of FIGS. 20-25. As illustrated in FIGS. 20 and 21, a swing armassembly 620 is provided that can include a swing arm 622 and a tipdresser 624. The swing arm 622 can selectively position the tip dresser624 with respect to welding tips of a spot welder (not shown) tofacilitate cleaning/dressing of the welding tips. The swing arm 622 caninclude a mounting base 626, an arm assembly 628 coupled to the mountingbase 626, and a driver cylinder 629 pivotally coupled to the mountingbase 626. The driver cylinder 629 can be operably mounted to the armassembly 628 to facilitate pivoting of the arm assembly 628 with respectto the mounting base 626. In one embodiment, the driver cylinder 629 canbe a pneumatic drive. In other embodiments, any of a variety of drivescan be used to facilitate powered pivoting of the arm assembly 628, suchas, for example, a servo. The arm assembly 628 can include an arm 630,an extendible arm mount 632, and a head 634. The extendible arm mount632 can be slidably coupled with the arm 630 and slidable along an axisA1 between a retracted position and an extended position. The head 634can be mounted to the extendable arm mount 632 and can be configured toaccommodate the tip dresser 624. The extendible arm mount 632 can beselectively extendible between the retracted position and the extendedposition to facilitate positioning of the tip dresser 624 with respectto welding tip. In one embodiment, the extendible arm mount 632 can bepositioned during initial setup of the swing arm 622 to allow forrepeated interaction with different welding tips without requiringrepositioning of the extendible arm mount 632.

The mounting base 626 can facilitate mounting of the swing arm assembly620 with fasteners (e.g., with bolts), to a floor, or at any of avariety of other suitable locations that allow the tip dresser 624 tointeract properly with the spot welding machine (not shown). Forexample, when the spot welding machine is operating, the swing arm 622can be in a stand-by position, such that the tip dresser 624 remains outof the operational zone of the spot welding machine. Once the weldingtips are ready for dressing, the spot welding machine can cease spotwelding, and the swing arm 622 can pivot the tip dresser 624 intoposition (via operation of the driver cylinder 629 and/or sliding of theextendible arm mount 632). The spot welding machine can then bring thewelding tips into contact with a cleaning mechanism (not shown) on thetip dresser 624 to facilitate dressing of the welding tips. In oneembodiment, the swing arm 622 can move the tip dresser 624 into placewithout requiring substantial movement of the spot welder. In anotherembodiment, the swing arm 622 and the spot welding machine can movetogether such that they meet at a predetermined location.

The head 634 of the swing arm assembly 620 can include a support plate638 that can be coupled with the rest of the head 634 with fasteners(not shown) or other suitable alternative securement arrangements.Referring now to FIGS. 22 and 23, the support plate 638 can include aplurality of attachment features that can facilitate the attachment of ashifter 670. The shifter 670 can include a body 672 and a slide plate674. The tip dresser 624 can be releasably coupled to the slide plate674 with fasteners (not shown) that can interact with holes 676 (FIGS.24 and 25) defined by the slide plate 674. It is to be appreciated thatthe tip dresser 624 can be coupled with the slide plate 674 through anyof a variety of suitable methods, such as through welding, for example.

The slide plate 674 can be slidable with respect to the body 672 alongan axis A2 between a first position (FIGS. 20-22) and a second position(FIG. 23). In one embodiment, the axis A2 can be substantially parallelwith the axis A1. When in the first position, the slide plate 674 can belaterally translated to a position proximate a distal end of the shifter670. When in the second position, the slide plate 674 can be laterallytranslated to a position proximate a proximal end of the shifter 670.Although the slide plate 674 is shown to travel along a single axis(e.g., A2) it will be appreciated that it the slide plate 674 canalternatively be configured to move along multiple axes.

The slide plate 674 can be moved between the first and second positionsto facilitate lateral movement of the tip dresser 624 relative to a weldtip. As illustrated in FIGS. 20-23, the tip dresser 624 can be a dualtip dresser that has a first cutting area 678 adjacent to a secondcutting area 680. The first cutting area 678 can have dull cuttingblades and the second cutting area 680 can have sharp cutting blades.Movement of the slide plate 674 between the first position and thesecond position can facilitate interaction of either the first cuttingarea 678 or the second cutting area 680 with a weld tip when the tipdresser 624 is moved into position (e.g., by the swing arm 622) to dressthe weld tip. For example, the swing arm assembly 620 can swing the tipdresser 624 into interaction with a weld tip with the tip dresser 624 inthe first position, such that the first cutting area 678 interacts withthe weld tip. Once the weld tip has been treated by the first cuttingarea 678, the swing arm 622 and/or the slide plate 674 can facilitatemovement of the slide plate 674 to the second position such that thesecond cutting area 680 interacts with the weld tip. In one embodiment,the swing arm 622 and/or the slide plate 674 can facilitate movement ofthe slide plate 674 directly from the first position to the secondposition. In another embodiment, when the slide plate 674 is in thefirst position and the treatment of the weld tip in the first cuttingarea 678 is complete, the swing arm 622 can then move the tip dresser624 enough to remove the weld tip from the first cutting area 678. Theslide plate 674 can then be moved to the second position, and the swingarm 622 can then swing the tip dresser 624 into interaction with theweld tip to locate the weld tip in the second cutting area 680 forsubsequent treatment thereof.

In some embodiments, the weld tip might only need to interact with oneof the first and second cutting areas 678, 680. Selection from betweenthe first and second cutting areas 678, 680 can depend on a variety offactors, such as, for example, the cutting requirement for the tips, theamount of buildup on the tip, the tip material used (e.g., aluminum orcopper), and/or any interference issues between the weld tips and thetip dresser 624 during the motion path. It will be appreciated that anysuitable position of the slide plate 674 among the first and secondpositions is contemplated, where such movement may help avoidinterference with weld tips or allow for precise positioning of thefirst and second cutting areas 678, 680.

Referring to FIG. 24, the body 672 can include a shell 682 that can beselectively removable to reveal various internal components. A pluralityof plugs 684 can be selectively inserted into the shell 682. Referringto FIG. 25, one embodiment of the shifter 670 is shown with the shell682 removed. The shifter 670 can include a base plate 686 upon which alinear guide rail 688 can be mounted. A linear guide carriage 690 can becoupled with the slide plate 674 and can be received in the linear guiderail 688. The linear guide carriage 690 can interact with the linearguide rail 688 to facilitate sliding of the slide plate 674 between thefirst and second positions. In one embodiment, the base plate 686 andthe linear guide rail 688 can be formed together in a unitary one-piececonstruction and the linear guide carriage 690 and the slide plate 674can be formed together in a unitary one-piece construction. In otherembodiments, the base plate and the slide plate 674 can include any of avariety of suitable alternative or additional features that facilitatesliding of the slide plate 674 between the first and second positions.

Adjustable position stoppers 692, 694 can be provided at each end of thelinear guide rail 688 to prevent the linear guide carriage 690 fromtravelling beyond the linear guide rail 688. The adjustable positionstoppers 692, 694 define the travel distance for the linear guidecarriage 690 and thus the slide plate 674. In one embodiment, theadjustable position stoppers 692, 694 can be selectively adjusted (e.g.,manually, remotely, and/or automatically) to define different traveldistances (e.g., for different applications). It is to be appreciatedthat the slide plate 674 can be positioned relative to the base plate686 in any of a variety of suitable alternative arrangements in additionto or in lieu of the adjustable position stoppers 692, 694. For example,the slide plate 674 can be positioned relative to the base plate 686 byan electrical servo or other powered positioning device in lieu of theadjustable position stoppers 692, 694.

A position sensor 696 can detect the position of the linear guidecarriage 690 (and thus the slide plate 674) along the linear guide rail688 and can communicate the position to a controller (not shown) tofacilitate automated positioning of the slide plate 674 and associatedtip dresser (e.g., 624). The controller can be a programmable logiccontroller (PLC) or any of a variety of other suitable additional oralternative controller. The controller can be associated withpre-programmed specifications, programs, and/or modes to facilitatechanges between operational needs.

Still referring to FIG. 25, the shifter 670 can include a firstpneumatic cylinder 698 and a second pneumatic cylinder 700 that isoperably coupled with the slide plate 674 and configured to slide theslide plate 674 towards the first position and the second position,respectively. The first and second pneumatic cylinders 698, 700 can befluidly coupled with one of a pair of pneumatic fittings 702 and poweredby a fluid source (not shown), such as a source of compressed air, forexample, that is coupled with the pneumatic fittings 702. Although acompact two-cylinder design is illustrated, other pneumatic cylinderdesigns and suitable number of cylinders are contemplated, such as asingle cylinder design. It will be appreciated that the slide plate 674can be actuated with any of a variety of suitable alternative powersources, such as electrically, for example. It is also to be appreciatedthat the shifter 670 can be any suitable shape or configuration,although a relatively flat box-shaped configuration may be beneficial toavoid interference.

FIGS. 26 and 27 illustrate another alternative embodiment of a head 834for a swing arm assembly, the head 834 being similar to, or the same asin many respects as, the head 34 illustrated in FIGS. 1-5. For example,a tip dresser 824 can be mounted to a support plate 838 of the head 834.However, a lift assembly 858 can be releasably secured to the supportplate 838 and can be operably coupled with the tip dresser 824. The liftassembly 858 can be configured to facilitate powered vertical movementof the tip dresser 824 for effective positioning of the tip dresser 824with respect to welding tips.

FIGS. 28 and 29 depict a front and back perspective view of the liftassembly 858 shown in FIGS. 26 and 27. The lift assembly 858 can includea mounting plate 860 and a slidable plate 862. The slidable plate 862can be slidably coupled with the mounting plate 860 and slidable withrespect to the mounting plate along an axis A3 to facilitate poweredvertical positioning of the tip dresser 824 with respect to weldingtips. The mounting plate 860 can be selectively coupled with the supportplate 838. The mounting plate 860 can define apertures 864 that canreceive one or a plurality of fasteners to attach the lift assembly 858to the support plate 838. A actuator 866 can be coupled with themounting plate 860 such that the actuator 866 is fixed to the mountingplate 860. The actuator 866 can be configured to facilitate selectivesliding of the slidable plate 862 with respect to the mounting plate860. The actuator 866 can include an piston 868 that is engaged with aflange 870 that is coupled with the slidable plate 862. The piston 868can be selectively extendible (e.g., pneumatically or electrically) tourge a flange 870 in a generally upward or downward direction. Theflange 870 can extend through a slot 872 defined by the mounting plate860. The slot 872 can be sized to support a desired range of motion forthe flange 870 as the piston 868 is urged in an upward or downwarddirection. The slidable plate 862 can be coupled with a tip dresser. Itwill be appreciated that the slidable plate 862 can be actuated alongany suitable axis, such as a substantially vertical axis, where the axisand range of movement can vary depending upon the needs of a specificapplication. It is also to be appreciated that any of a variety ofsuitable alternative arrangements for moving and/or selectivelypositioning the slidable plate 862 with respect to the mounting plate860 are contemplated. For example, the mounting plate 860 and theslidable plate 862 can be movable coupled together via internallymachined features such as a worm gear or other mechanism that isselectively driven by a suitable motive source. In another example, amotive source can be integrated directly into one of the mounting plate860 and the slidable plate 862 to facilitate movement therebetween.

There may be a number of advantages to the system described in FIGS.26-29 When a swing arm is in the “work” position, a valve (not shown)can actuate the actuator 858 attached to the slidable plate 862. Theactuator 858 can extend or retract to push or pull the slidable plate862 on which the dresser is mounted until a stationary cap is almosttouching the cutter blade of the tip dresser. Such a design can maximizeweld cap life, where in a standard application, the moveable cap on theweld gun generally closes on the tip dresser and compresses theself-equalizing springs on the tip dresser until the cutter blade makescontact with the stationary cap. With such systems the moveable weld capis being dressed while it is pushing the dresser down towards thestationary cap, causing uneven amounts of material removed from eachcap. The lift assembly 858 may provide for a more even amount ofmaterial being removed from each cap by controlling the position of thetip dresser relative to the cap. The actuator 866 and associated piston868 can be associated with any suitable controller or control logic toprecisely and/or optimally position the tip dresser.

FIG. 30 depicts a side view of the lift assembly 858 coupled with a tipdresser 824. The lift assembly 858 can include an adjustment screw 872,which can be coupled with the slidable plate 862, to allow an operatorto control the work position of the moveable plate 862. The workposition can be the position where tip dressing occurs. It will beappreciated that any suitable adjustment mechanism can be provided toimprove the accuracy of position of the tip dresser.

FIG. 31 depicts a partial perspective view showing only the slidableplate 862 of the lift assembly 858 coupled with the tip dresser 824. Theslidable plate 862 can define a plurality of apertures 874 or otherattachment features to facilitate coupling with the tip dresser 824. Thelift assembly 858 can include a pair of rails 876 and a pair of tracks878 that are coupled with the mounting plate 860 and the slidable plate862, respectively, and cooperate with each other to facilitate slidingof the slidable plate 862 with respect to the mounting plate 860. In oneembodiment, the pair of rails 876 can be releasably attached to themounting plate 860 and the pair of tracks 878 can be mounted to theslidable plate 862. The rails 876 can include an elongate body 878having a neck 880. The neck 880 of the rails 876 can engage the tracks878 such that the rails 876 are slidable, but not detachable, from thetracks 878. Such a configuration can facilitate relative movementbetween the moveable plate 862 and the mounting plate 860 while keepingthe plates 860, 862 securely coupled together. The incorporation ofdedicated rails and tracks can also reduce wear and tear that may beassociated with two plates directly rubbing against one another duringuse.

FIG. 33 illustrates a front view of the lift assembly 858 taken alongthe line 33-33 in FIG. 32. As illustrated in FIG. 33, the rails 876 canbe coupled with the mounting plate 860 and tracks 878 can be coupled tothe slidable plate 862. Any suitable relationship between the slidableplate and the mounting plate is contemplated. As illustrated in FIG. 33,the mounting plate 860 and the slidable plate 862 can also cooperate todefine a cavity 882 in which any suitable tracks, rails, mountingfeatures, or the like, can be contained. Providing such a cavity canconceal tracks and the like that could present a pinch hazard duringoperation.

It is to be appreciated that in some embodiments a swing arm assemblycan include a linear servo actuator, a linear electromechanicalactuator, a rotary servo, a motor associated with a gearbox, or any of avariety of suitable alternative arrangements that is/are operable tofacilitate pivoting of an arm assembly with respect to a mounting base.An example of such a swing arm assembly is disclosed in U.S. patentapplication Ser. No. 15/286,007 which is incorporated herein in itsentirety.

The foregoing description of embodiments and examples has been presentedfor purposes of illustration and description. It is not intended to beexhaustive or limiting to the forms described. Numerous modificationsare possible in light of the above teachings. Some of thosemodifications have been discussed and others will be understood by thoseskilled in the art. The embodiments were chosen and described forillustration of various embodiments. The scope is, of course, notlimited to the examples or embodiments set forth herein, but can beemployed in any number of applications and equivalent devices by thoseof ordinary skill in the art. Rather, it is hereby intended that thescope be defined by the claims appended hereto.

1-20. (canceled)
 21. A swing arm assembly comprising: a tip dresser fora spot welding machine; a flange coupled with the tip dresser; and aswing arm comprising: a mounting base; and an arm assembly comprising:an arm pivotably coupled with the mounting base; an extendible arm mountdisposed within the arm and slidably coupled with the arm such that theextendible arm mount is slidable with respect to the arm along a firstaxis between a retracted position and an extended position; and a headmounted to the extendible arm mount and comprising: a support plate; andan actuator coupled with the support plate, wherein:  the tip dresser iscoupled with the support plate; and  the actuator is operably coupledwith the flange to facilitate selective sliding of the tip dresser withrespect to the support plate.
 22. The swing arm assembly of claim 21wherein the actuator comprises a piston.
 23. The swing arm assembly ofclaim 22 wherein the piston is electrically powered.
 24. The swing armassembly of claim 21 further comprising a driver cylinder pivotallycoupled to the mounting base, the driver cylinder being operably mountedto the arm assembly to facilitate pivoting of the arm assembly withrespect to the mounting base about a second axis that is perpendicularto the first axis.
 25. The swing arm assembly of claim 24 wherein thedriver cylinder comprises a pneumatic drive.
 26. The swing arm assemblyof claim 21 wherein the actuator facilitates selective sliding of thetip dresser in a direction that is perpendicular to the first axis. 27.A swing arm assembly comprising: a tip dresser for a spot weldingmachine; a flange coupled with the tip dresser; and a swing armcomprising: a mounting base; and an arm assembly pivotably coupled withthe mounting base, the arm assembly comprising: an arm; an extendiblearm mount disposed within the arm and slidably coupled with the arm suchthat the extendible arm mount is slidable with respect to the arm alonga first axis between a retracted position and an extended position; anda head mounted to the extendible arm mount and comprising: a supportplate; a mounting plate coupled with the support plate; and an actuatorcoupled with the mounting plate, wherein:  the tip dresser is coupledwith the mounting plate; and  the actuator is operably coupled with theflange to facilitate selective sliding of the tip dresser with respectto the support plate.
 28. The swing arm assembly of claim 27 wherein theactuator comprises a piston.
 29. The swing arm assembly of claim 28wherein the piston is electrically powered.
 30. The swing arm assemblyof claim 27 further comprising a driver cylinder pivotally coupled tothe mounting base, the driver cylinder being operably mounted to the armassembly to facilitate pivoting of the arm assembly with respect to themounting base about a second axis that is perpendicular to the firstaxis.
 31. The swing arm assembly of claim 30 wherein the driver cylindercomprises a pneumatic drive.
 32. The swing arm assembly of claim 27wherein the actuator facilitates selective sliding of the tip dresser ina direction that is perpendicular to the first axis.
 33. A swing armassembly comprising: a swing arm comprising: a mounting base; and an armassembly pivotably coupled with the mounting base, the arm assemblycomprising a head that comprises a support plate; a tip dresser for aspot welding machine, the tip dresser being slidably coupled to thesupport plate and slidable with respect to the support plate; at leastone self-equalizing spring that is configured to oppose the sliding ofthe tip dresser with respect the support plate; a flange coupled withthe tip dresser; and an actuator coupled with the head, wherein theactuator is operably coupled with the flange to facilitate selectivesliding of the tip dresser with respect to the support plate.
 34. Theswing arm assembly of claim 33 wherein the arm assembly comprises: anarm; and an extendible arm mount disposed within the arm and slidablycoupled with the arm such that the extendible arm mount is slidable withrespect to the arm along a first axis between a retracted position andan extended position, wherein the head is mounted to the extendible armmount.
 35. The swing arm assembly of claim 33 wherein the actuatorcomprises a piston.
 36. The swing arm assembly of claim 35 wherein thepiston is electrically powered.
 37. The swing arm assembly of claim 34further comprising a driver cylinder pivotally coupled to the mountingbase, the driver cylinder being operably mounted to the arm assembly tofacilitate pivoting of the arm assembly with respect to the mountingbase about a second axis that is perpendicular to the first axis. 38.The swing arm assembly of claim 37 wherein the driver cylinder comprisesa pneumatic drive.
 39. The swing arm assembly of claim 34 wherein theactuator facilitates selective sliding of the tip dresser in a directionthat is perpendicular to the first axis.